IUBMB Enzyme Nomenclature


Accepted name: zealexin A1 synthase

Reaction: (S)-β-macrocarpene + 3 O2 + 3 [reduced NADPH—hemoprotein reductase] = zealexin A1 + 4 H2O + 3 [oxidized NADPH—hemoprotein reductase] (overall reaction)
(1a) (S)-β-macrocarpene + O2 + [reduced NADPH—hemoprotein reductase] = [(4S)-4-(5,5-dimethylcyclohex-1-en-1-yl)-cyclohex-1-en-1-yl]methanol + H2O + [oxidized NADPH—hemoprotein reductase]
(1b) [(4S)-4-(5,5-dimethylcyclohex-1-en-1-yl)-cyclohex-1-en-1-yl] methanol + O2 + [reduced NADPH—hemoprotein reductase] = (4S)-4-(5,5-dimethylcyclohex-1-en-1-yl)cyclohex-1-ene-1-carbaldehyde + 2 H2O + [oxidized NADPH—hemoprotein reductase]
(1c) (4S)-4-(5,5-dimethylcyclohex-1-en-1-yl)cyclohex-1-ene-1-carbaldehyde + O2 + [reduced NADPH—hemoprotein reductase] = zealexin A1 + H2O + [oxidized NADPH—hemoprotein reductase]

For diagram of reaction click here

Glossary: (S)-β-macrocarpene = (1'S)-4',5,5-trimethyl-1,1'-bi(cyclohexane)-1,3'-diene
zealexin A1 = (4S)-4-(5,5-dimethylcyclohex-1-en-1-yl)cyclohex-1-ene-1-carboxylate

Other name(s): CYP71Z18 (gene name)

Systematic name: (S)-β-macrocarpene,[reduced NADPH—hemoprotein reductase]:oxygen oxidoreductase (zealexin A1-forming)

Comments: A cytochrome P-450 (heme thiolate) enzyme characterized from maize. The enzyme sequentially oxidizes(S)-β-macrocarpene via alcohol and aldehyde intermediates to form zealexin A1, a maize phytoalexin that provides biochemical protection against fungal infection.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:


1. Mao, H., Liu, J., Ren, F., Peters, R.J. and Wang, Q. Characterization of CYP71Z18 indicates a role in maize zealexin biosynthesis. Phytochemistry 121 (2016) 4-10. [PMID: 26471326]

[EC created 2018]

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